While one Tigers prospect tries to change his luck in the Arizona Fall League, another is trying to escape the bad luck of the injury bug. Left-hander Rob Henkel, arguably the top pitching prospect in the farm system, will have tests conducted on his back after stiffness escalated over the past couple of weeks. While it's too early to make an evaluation, Henkel is out of action until doctors figure it out.

Henkel battled through two weeks to go 0-2 with a 10.38 ERA in his first three starts for the Grand Canyon Rafters. He gave up three runs in four innings last week and had shown improvement from his previous two outings.

"I've gotten to know this kid and he wants to compete," said Grand Canyon pitching coach Britt Burns, who coached Henkel all season at Double-A Erie. "This is a kid who works his tail off to compete. It's just a frustrating thing."

If Henkel is unable to go for a while, current Tiger Matt Roney could see some starts in Arizona. Roney, who made 11 starts for Detroit as a Rule 5 draft pick, is scheduled to join the Rafters this weekend for an assignment.

Henkel, 25, is pitching in Arizona in part to make up for the time he spent on the disabled list while with Erie. Back and shoulder problems landed him on the DL more than once, with the latter stint finishing up just as the Double-A season was coming to an end.

Despite the time lost, Henkel was the Seawolves' ace with a team-best 9-3 record as a starter, striking out 70 batters in 82 2/3 innings. His 3.38 earned-run average would have ranked eighth in the league had he compiled enough innings to qualify. His knuckle-curveball, a pitch fans saw out of Mike Mussina in Game 3 of the World Series, can be devastating when mixed with his other offerings.

"When this guy's been able to pitch healthy, he's legitimate," Burns said.

So, for that matter, is fellow Erie pitcher Preston Larrison when he's on. The 22-year-old right-hander was the winning pitcher in this summer's All-Star Futures Game in Chicago, but struggled to a 4-12 record and 5.61 ERA during the Eastern League season. His work out of the bullpen in Arizona will hopefully put that behind him.

In four relief appearances, Larrison's numbers would read like a decent start. He's scattered seven hits and two walks over eight innings. Three of those hits have been home runs, accounting for his six earned runs allowed. Much of that damage came last weekend against Team USA in its preparation for the 2004 Olympics.

The upside of Larrison relieving, Burns said, is that it allows him to think one inning at a time. "He's doing a nice job of establishing his sinker," Burns said. "He's enjoying doing this here, and he might be enjoying having some success."

The other Tigers product in the Rafters bullpen, Lakeland right-hander Mark Woodyard, entered the week with nine strikeouts in his first seven innings against nine hits and four runs allowed. He pitched two scoreless innings Oct. 9 with two strikeouts against Scottsdale.

Here's a look at the Tigers hitting prospects in the Fall League:

Donald Kelly: Kelly scorched up the desert from season's start, hitting in five of his first six contests before cooling off. He went 3-for-4 with a solo homer and a stolen base Oct. 7 against Peoria. Playing mostly third base, his three steals lead the team.

Nook Logan: The Tigers' center fielder of the future continues to show flashes that his athletic ability is translating at the plate. After a slow start enveloped much of the month, he went 3-for-5 Tuesday with a double, triple and three runs scored. All three hits, moreover, were hard-hit balls.

Max St. Pierre: Like Kelly, St. Pierre got off to a solid start offensively before leveling out. He went 3-for-4 with two doubles and two runs scored Oct. 9. Unlike Kelly and Logan, St. Pierre is also adjusting to a platoon role, splitting time at catcher with Yankees prospect Michel Hernandez. Instructional league notes: Minor-league field coordinator Glenn Ezell's first offseason in charge of the Tigers fall instructional league has placed him with the best of the Tigers' recent drafts. Three of Detroit's top 10 prospects entering the season and each of its top 10 draft signings are spending extra time in Lakeland.

Among those who have stood out is third baseman Kody Kirkland, part of the return from last fall's Randall Simon trade with Pittsburgh and an All-Star this summer at short-season Class A Oneonta. He was one of three Tigers among the NY-Penn League's top 10 hitters along with Eric Rodland and Tony Giarratano.

"This guy's a good ballplayer," Ezell said. "He's just nice to watch him play every other day. He's got some intensity, likes to do what he's doing and he's going to be pretty good at it when the year's over."

Giarratano and Rodland are also in the instructional league.

Among the other instructional league projects is Curtis Granderson, who continues his adjustment to center field from earlier this summer at Class A Lakeland. Likewise, David Espinosa continues to learn how to be a corner outfielder as the Tigers try to take advantage of his shortstop-quality arm.

Instructional league also marks the first real pro experience for draft picks Kyle Sleeth and Cody Collet, who missed summer play in the minor leagues. Sleeth, the third overall pick out of Wake Forest, was essentially given the summer to rest his arm. Collet, a sixth-round pick out of high school and potential top catcher in the farm system, signed with the Tigers in August after weighing pro ball against the chance to play college ball at Fresno State.

"He's been doing quite well for his age," Ezell said of Collet. "His aptitude is very good. His athletic ability is good. But he's an 18-year-old in pro ball."